This invention relates to a seat lock device for stepwise locking in a desired inclined position a swingable member or back rest of a rear seat of, for example, an automobile which is rotatably supported on a shaft mounted on an immovable member.
Various types of seat lock device proposed to date have the drawbacks that since the seat lock device lies very close to a pivotal shaft of a seat, a tremendous force is applied on the seat lock device where the back rest is suddenly locked or subjected the heavy load, probably leading to the damage of said seat lock device and in consequence making it necessary to manufacture the seat lock device with an extremely great mechanical strength.
To eliminate the above-mentioned drawbacks, there was devised a seat lock device for locking a back rest at a point spaced from the pivotal shaft of the seat. However, this prior art seat lock device failed to meet a demand for a seat lock device of simple construction capable of changing the inclined position of the back rest in a plurality of stages. For example, with a light van type automobile provided with a cargo section behind a rear seat, the back rest of the rear seat is so supported as to swing back and forth. Hitherto, however, the back rest could only take two positions, that is, a normal position adapted for a rider to be seated and a position thrown forward in a substantially horizontal direction to enlarge a floor space for carriage of a large amount of cargo. Further disadvantages of the prior art seat lock device are that where it is desired to carry a large amount of cargo, the back rest can not be changed and held in the upright position, but has to be folded substantially flat, preventing a rider from being seated on a rear seat, and that where a small amount of cargo is carried, the rider can not enjoy a comfortable seated position by reclining the back rest backward from the normal position.